Autism is a tremendously heterogeneous disorder with complex genetic and neural underpinnings. This grant aims to understand variability in the autism phenotype by examining links between known genetic risk factors for autism and brain structure and function. We will recruit 80 children with autism and 40 controls who will undergo a comprehensive phenotyping assessment, high field structural MRI, and functional MRI using three tasks that differentiate typically developing children from those with autism, and which tap into core deficits seen in ASD. Our study will focus on five autism risk polymorphisms and one known genetic syndrome, 22q11deletiion with the goal of identifying structural and functional brain abnormalities that are linked to autism risk polymorphisms, and in turn to link these neural anomalies to variations in the autism phenotype. We hope to develop profiles of imaging phenotypes in autism that will help identify valid autism subtypes based on brain structure and function, and link these phenotypes to their genetic origins, thereby moving towards a more crystallized conceptualization of ASD. PUBLIC HEALTH RELEVANCE: This grant aims to examine the effects of 5 replicated autism risk genes on brain structure and function, using functional and structural MRI. The goal is to try to understand the neural basis of behavioral variations in autism by drawing connections from genes to brain to behavior. We will examine 5 autism risk genes and one known genetic syndrome, 22q11deltion, where there are high rates of autism, and identify brain regions and systems associated with these genes, relating them to variations in the autism phenotype.